Composition and process for rubber blanket printing



Patented Nov. 15, 1932 GEORGE w, B NNET or CINCINNATI, oHIo Drawing.

The present invention relates toimprovements'in printing with blankets, for example printing on offset printing presses,or the like,

or pr ntingin anyjkind of a process where'a printers blanket is employed. The offset press will be discussed in connection with the invention, this being a well known type of press used in the printing industry. In the F ordinary process of printing with an offset press, the type, or an engraved or etched plate or-the like, is first brought into contact, while mounted on a roller, with aninked roller, in

order to ink the face of the type or the desired portions of the engraved or etched plate.

During therotation of the roll, carrying the type,"the face of the type comes into contact witha rubber blanket mounted on a roller, leaving ink on the said rubber blanket, the

roller carrying the blanket thenrevolves furthe! and a sheet of paper passes between the blanket roll'anda pressure roll, in order to transferthe ink from the rubber blanket onto the paper. The roller carrying the'type and the roller carrying the blanket must of course rotate at exactly the same speed, but in-opposite directions, The face of the inking roller should travel at the same speed as the face of thetyperoller, and the face of the pressure roller should travel atthe same speed as the face of theblanket roller, although the pressure rollen'and inking roller may be of a larger or sm'aller size than the type roller and blanket roller. 1 i

skilled-printer or pressman willreadily understand what is meant by the term make ready. Briefly, it is that operation involving the building up or patching a packing with folio or similar thin transparentpaper at, those portions where a faint impression or perhaps, where there is noimpression, whatever and also cutting out those portions where -the'impression is too. great,with the final result that an'even impression is obtained over all portions of the printing surface. This packing is placed under the rubber on the cylinder and often constitutes several sheets of. paper" carrying patches. This make ready operation when performed in the ordinary manner is very time consuming and in: printing'jobs involving cuts, very PATENT o comrosrrfoN AND rnocnss ronRUBBEnBLANKET PRIN INGQ Application filed September 5,1930. ser1a1 4so,o25.

FFIcEgi oftenrequires 10 to l8hours to tmakeready if:

'Inpracticin'g my invention, it is possible to greatly. reduce the time requiredfor making ready, because Imerelyapply a composition to therubber 'on the printing. cylinder wherehence, I avoid the usual steps. of marking out a trial sheet and patching withfolio. This composition which ishereafter described should be applied :to the "printing blanket preferably about a day. before the printing blanket is placed on the cylinder of the press. The time during which the blanket-is allowed to stand aftertreatment with myjnovel composition will of course vary withvthegjcondif tion of the rubber and I have found that where a rubber is in good :conditiononehour I I tween the blanket roller and therpressure roll er. Heretofore when mashingof the blanket has occurred, it has usually been necessary to disconnectzone end of the blanket; after 7 stopping the press, and thenbuild up with small carefully cut outpieces of. paper, one or several thicknesses, onthe backorfabric side of the blanket, to build upthe desired thickness sin'cethe face of the. blanketroll must be true, inorder to produce satisfactory printing This patching ofthe blanket requires much'time, particularly when the,

mashes are bad or are uneven. Incommon practice, after patching has been resorted't'o, and the blanket fastened again onto the roller, the usual practice has been to wash the face of the blanket with benzine,for example with a sponge or'the like,in order'to remove all ink, dried ink and the like, and'to then powder the surface with finely powdered sulphur, or with a mixture of finely powdered jsulphurand Y finely powdered French .chalk (tal c) A further objection to blanket printing is that sometimesthe blanket becomes embossed.

a by'all cavitiesand depressions are filled in and This embossing may be produced by certain special inks which carry considerable amount of oil particularly drying oils, and by overpacking (producing extra pressure) and various other ways. After a particular printing job has been completed, or when the embossing gets too bad, the usual practice has been to remove and discard the printers blanket from the roll.

From the above causes and from the other causes, which cause injury and deterioration of the printers blanket, a blanket hasa use ful life period varying from one day to three months, but it may be stated that the average useful life period of a blanket is ordinarily about two months. 1

In accordance with the present invention, I have found that small mashes which arenot very deep, on the rubber surface of the blanket can readily be overcome by the use of a single application of a composition as herein described, whereas deeper or larger mashescan readily be overcome by applying the composition to both the frontand the-back of the blanket, the application to the blanket of the composition in question being much more expeditious than the paper packing hereto fore usually resorted to.

The composition preferably employed is made up as follows Kerosene 1 7 ounce Spirits of .turpentine '1 ounce Penetrating oil largely V composed of hydrocara 'bons 1 ounce ()ilof Sassafras 0.5 ounce Oilof cloves 0.5ounce Powdered sulphur 1 teaspoonful Powderedorris root u 2 teaspoonfuls together with any suitable color. The color is for example Prussian blue ground in a drying oil or mixture of drying oil and japan drier. q

The hydrocarbon oil used in.the"penetrating oil may be kerosene or similar distillate of petroleum, mixed with say an equal amount of coal tar creosote, this being very satisfactory for the purpose, although other penetrating oils can be employed.

In place of kerosene, the first mentioned ingredientof the composition, I may use other relatively light petroleum distillates, preferably less volatile than gasoline and preferably more volatile thanspindle'oil.

The oil of Sassafras and oil of cloves impart a pleasant odor to the oil mixture but they also have an important function of swelling the rubber 'and penetrating the rubber "readily, and these also penetrate andswell the fabric face the blanket. 7

It is to be understood that before applying when applied to the back of the above compositionto the face of the blanket,- either the whole face of the-blanket or the portion thereof carrying the mashes are first washed with benzine, in order to remove the inktherefrom. Small mashes which are on the surface of the rubber blanket will ordinarily be cured simply by applying the above mentioned composition on the rubber surface, whereas larger or deeper mashes are preferably treated first on the (surface and then on the back of the blanket (fabric side). For application either to the front or back 7 of the blanket, a small quantity of the liquid material, say on a sponge or wad of cotton is simply'rubbed upon the blanket, and the composition is then allowed to dry, which r quires only a few min utes. The finely powdered sulphur or a mixture of the same with finely powdered talc is then 'applied'to the surface as above indicated, the blanket then looked back upon the roller in the customary manner and the printing at once continued with. While ordinary patching may require a good deal of time, mashes can be cured according to the present invention in a small fraction only of thetime required by'the method heretofore commonly used.

-Where the blanket has become embossed, as above referred to, it is only necessary to apply the composition of the present case, on .and around the embossed portion of the blanket, this being also preferablydone-after first washing with benzine. Af-teridrying, the coating of fine sulphur is applied as above referred-t0. Y q g In accordance with the presentinventionit has been found that the same blanketcan be i used for amonth or even several months, in place of a few days as has been thecustom heretofore. a a

In the caseof rubber blankets which'have become embossed it may be suflicient to apply 195 this composition on the face side of the blanket or in somecases it is advisable to apply it on the face side and on the backboth. This is done primarily for the SOftBHlIlg-fififid? upon the-embossed portion of jthe rubber. Treatment on embossed blankets may result' only in a temporary elimination of the embossing effect, which may come "back after a time, sometimes after several hours or after a day or more. In the case of the mashes :however the treatment as described herein cures the mashes so that they are permanently cured and do not reappear on continuation'of the use of the blanket.

It can be seen from the foregoing that my process is applicable not only to making ready a blanket or matrix in the firs't instance but is also applicable in the repairof damaged blankets or matrices. I

'1."A composition of matter adapted for being applied to the face side or rear side of rubber printing blankets, .the same beingra liquid containing as a'vehicle, a liquid mineral oilproduct less volatile than gasoline f and more volatile than spindle oil, spirits of turpentine, a penetrating oil consisting largely of hydrocarbons, oil of sassafras and oil of cloves, such vehicle carrying small amounts of powdered sulphur and powdered orris root. 7

2. A composition of matter adapted for being applied to the face side or rear side of rubber printing blankets, the same being a liquid containing as a vehicle, a liquid mineral oil product less volatile than gasoline and more volatile than spindle oil, spirits of turpentine, a penetrating oil'consisting largely of hydrocarbons, oil of Sassafras and oil of cloves, such vehicle carrying small amounts of powdered sulphur .and powdered orris root, together with a pigment ground in a readily drying oil. Y

3. A liquid mass comprising the. following materials in approximately the proportions stated, namely,

Kerosene oil 1 ounce Spirits of turpentine 1- ounce Penetrating oil, largely hydrocarbons 1 ounce Oil of sassafras 0.5 ounce Oil of cloves 0.5. ounce Powdered sulphur 1 teaspoonful Powdered orris root 2 teaspoonfuls and color in a drying1 oil, to give a color.

4. A process whic comprises applying to the face side of rubber printing blankets, a

liquid flowable composition comprising hydrocarbon oil of a gravity intermediate the gravities of gasoline and spindle oil, spirits of turpentine, penetrating oil consisting largely of hydrocarbons, oil of sassafras and oil of cloves, and containing finely powdered sulphur and finelypowdered orris root, said application being made on mashed portions of the blanket, and thereafter dusting with a fine solid containing sulphur.

5. A process as in claim 4, in which the said material is also applied to the back side of the blanket, in the vicinity of mashes, and thereafter dustingwith a fine solid containing sulphur. V

6. A process which comprises applying on and around mashed portions and embossed portions of at least one surface of a rinters blanket, the composition set forth P in claim 2, and dusting the surface with a composition containing dry sulphur.

7. A process which comprises applying on and around mashed portions and embossed portions of at least one surface of a printers blanket, the composition set forth in claim 3, and dusting the surface with a composition containing dry sulphur;

8. A process as set forth in claim 4, as applied to new rubber printing blankets whereby the usual make ready operation is dis pensed with.

which the said composition is applied to the back of a new blanket a period of time before its use on' the press varylngfrom one hour to 9. A process as set forth'in claim 4, in 

